Dec
6
Don’t count on air capture
House et al., writing in PNAS, suggests that directly removing CO2 from the atmosphere may cost in excess of $1,000/tonne, based on their techno-economic analysis:
Our empirical analyses of operating commercial pro- cesses suggest that the energetic and financial costs of capturing CO2 from the air are likely to have been underestimated. Specifically, our analysis of existing gas separation systems suggests that, unless air capture significantly outperforms these systems, it is likely to require more than 400 kJ of work per mole of CO2, requir- ing it to be powered by CO2-neutral power sources in order to be CO2 negative. We estimate that total system costs of an air capture system will be on the order of $1,000 per tonne of CO2, based on experience with as-built large-scale trace gas removal systems.
They mention biomass combustion with CCS as an alternative approach that, while scale-limited, may be somewhat less costly (probably $150-$400/tonne).
